[spirv-reader][ir] Fix premerge calculation.
When determining the premerge block for an `if` instruction, make sure
we don't select a walk stop block (like a `merge` instruction). This
block can't be a premerge block as it has to come after the `if` merge
block itself.
Change-Id: I973fde66cf790d002562dcf19021d35462c8c4f4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/245335
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Reviewed-by: James Price <jrprice@google.com>
diff --git a/src/tint/lang/spirv/reader/parser/branch_test.cc b/src/tint/lang/spirv/reader/parser/branch_test.cc
index 566c562..a0d7b17 100644
--- a/src/tint/lang/spirv/reader/parser/branch_test.cc
+++ b/src/tint/lang/spirv/reader/parser/branch_test.cc
@@ -520,21 +520,21 @@
%main_start = OpLabel
OpBranch %10
%10 = OpLabel
- OpLoopMerge %merge %cont None
+ OpLoopMerge %99 %80 None
OpBranch %20
%20 = OpLabel
%foo = OpIAdd %i32 %one %two
OpSelectionMerge %50 None
OpBranchConditional %true %30 %40
%30 = OpLabel
- OpBranch %merge
+ OpBranch %99
%40 = OpLabel
- OpBranch %merge
+ OpBranch %99
%50 = OpLabel
OpUnreachable
- %cont = OpLabel
+ %80 = OpLabel
OpBranch %10
- %merge = OpLabel
+ %99 = OpLabel
%foo2 = OpCopyObject %i32 %foo
OpReturn
OpFunctionEnd
@@ -553,22 +553,13 @@
exit_loop %3 # loop_1
}
}
- if true [t: $B6, f: $B7] { # if_2
- $B6: { # true
- %4:i32 = let %3
- ret
- }
- $B7: { # false
- unreachable
- }
- }
unreachable
}
$B3: { # continuing
next_iteration # -> $B2
}
}
- %5:i32 = let %2
+ %4:i32 = let %2
ret
}
}
diff --git a/src/tint/lang/spirv/reader/parser/parser.cc b/src/tint/lang/spirv/reader/parser/parser.cc
index 7801b9c..fe9c4e8 100644
--- a/src/tint/lang/spirv/reader/parser/parser.cc
+++ b/src/tint/lang/spirv/reader/parser/parser.cc
@@ -1851,6 +1851,11 @@
true_blocks.pop_back();
false_blocks.pop_back();
}
+
+ // If this is already a stop block, so it can't be a premerge
+ if (id.has_value() && walk_stop_blocks_.contains(id.value())) {
+ return std::nullopt;
+ }
return id;
}
